Djokovic through to semis

Roddick went into the match needing to win in straight sets to keep alive his hopes of progress, but the match proved to be a damp squib as Djokovic dominated from start to finish.

"It's a great achievement to reaching the semis," said Djokovic.

"It's great for the tournament to have the top four guys in the semis. It's a big challenge for all of us."

The Serbian was a break point down in the opening game of the match, but Roddick failed to convert in walloping a backhand into the net.

The night quickly went downhill for Roddick as Djokovic broke to move 3-1 ahead before wrapping up the opening set with a break in the final game of the set to take it 6-2.

With Djokovic needing to win only the first set to secure a place in the last four, the second set was always going to be an anti-climax.

Djokovic was desperate to conserve energy by getting off court with a disheartened Roddick facing a third straight defeat after losses to Rafael Nadal and Tomas Berdych earlier in the week.

Djokovic needed only one more break to secure the second set, and was presented it at 30-40 in the fourth game as Roddick slipped in his first double fault of the night.

Roddick gave glimpses of an unlikely recovery when he went 30-0 up at 3-5 in the second, but a couple of aces and two booming serves were enough to secure Djokovic matchpoint.

He needed only one as Roddick walloped a forehand into the net with a shot that summed up his struggles on the night.

World number one Rafael Nadal faces Andy Murray in the opening semi-final on Saturday afternoon at 2pm with Djokovic taking on Federer at 8pm.